1. Field of the Invention
The present invention relates to a data communication system installed in an electric machine such as automobile, airplane each including an electrically conductive body insulated from the ground, the system transmitting and receiving information between two different locations in the electric machine.
2. Description of the Related Art
One of conventional data communication systems of the aforesaid type comprises a plurality of communication terminals disposed at a plurality of locations in a vehicle body so that the communication terminals are connected to each other by a transmission path. Each communication terminal converts information to electric signals, thereby transmitting and receiving the electric signals. For example, JP-A-2001-16281 discloses such a communication system.
Another conventional data communication system comprises a tire pressure detector mounted on a wheel and tire monitor device installed on a vehicle body. Information about inner pressure of a tire is transmitted and received by radio between the tire pressure detector and the tire monitor device. For example, JP-A-2005-119370 discloses such a communication system.
However, arrangement of the transmission path is difficult in the data communication system including the communication terminals connected to each other by the transmission path. As a result, installation of the system in the vehicle is troublesome. On the other hand, the conventional data communication system carrying out wireless communication by radio waves can easily be installed in a vehicle. However, there are problems of large power consumption and possibility of producing radio interference with other vehicles.